The present invention relates to thermal collectors of solar energy, and more particularly to such collectors that are adapted for installation in the roof structure of a building.
A thermal collector of solar energy collects energy of the sunshine that is incident upon the collector. The collected energy is transferred as heat to a heat using apparatus such as a heat pump, a home heating or air conditioning system, or steam generating equipment in a power plant.
Typically, a number of thermal collectors is required to collect an amount of energy that satisfies the heat input requirement of the heat using apparatus, and such number usually increases when the heat input requirement is increased. To satisfy the heat input requirement of power plant steam generating apparatus, for example, a large number of collectors is required, covering a substantial area on which sunshine is incident. To satisfy the heat input requirement of a home air conditioning system, as another example, may require a number of collectors so great that the area occuplied by the collectors exceeds the roof area of the home. The number of collectors is reduced, however, by raising the efficiency at which heat is used by the heat using apparatus.
Various collector designs have been proposed. In some designs moisture may condense within the collector, limiting the efficiency of collection and diminishing the operating lifetime of collector elements. In other designs a medium which delivers heat to the heat using apparatus may freeze under various low temperature conditions. Still other designs require extensive modification of the roof structure in which the collectors are installed. In one class of proposed collectors, air may leak into the collector, corroding collector elements and diminishing the efficiency of collection.
There appears to be a need for a thermal collector which is adapted to operate at elevated temperatures, to increase the efficiency of the heat using apparatus and thereby to decrease the number of collectors required to satisfy the heat demand of such apparatus, and which is adapted for installation in a roof without extensive modification of the roof structure. It is desirable to provide such a collector whose operating lifetime and efficiency remain undiminished in the face of widely changing conditions of climate to which the collector is exposed.
The description of prior art herein is made on good faith and no representation is made that any prior art considered is the best pertaining prior art nor that the interpretation placed on it is unrebuttable.